Flop board isn't too bad for my range, but I guess check behind is better than betting small with this hand.

Turn, not too sure, but I think it's a call, still beating his bluffs and have good outs.

River checking back feels nitty, but I am a bit scared to bet here. I think often times it will just be a split vs AK, but he could still have AQ, even the offsuited ones, AA, QQ and KJs. Not sure how often he would go for a slowplay though, probably not too often. So do I have a clear value bet? If yes which size? And what to do against a x/jam?

Pre calling is probably better than jam, but jam is still much better than fold.

Flop, shouldn't turn into a bluff, no. GTO-wise you have to mix in some AK stabs, but I wouldn't.

Turn he tells you what he has with the size. KQ, QJ, JJ, AT, basically. But I don't think you can do anything but call. River then, given that range, easy value bet, however hard to get called, so do the same he did, tiny bet.